Entrusting Laser Trackers With Critical Measurements For Nearly Two Decades

BAE Systems - England

BAE Systems is a global company engaged in the development, delivery and support of advanced defence and aerospace systems in the air, on land and at sea. As one of the largest defence companies in the world and the largest such contractor in Europe, the company plays an important role in global military aircraft production. The company’s Typhoon, Tornado and Harrier fighter-bombers are all front line aircraft of the Royal Air Force. BAE Systems is also a major partner in the F-35 Lightning II program and produces the Hawk Advanced Trainer. Investing about 10 percent of its revenues into research and development, BAE Systems has always been at the forefront of what is technologically possible in the world of industrial metrology. The company’s cooperation with Leica Geosystems dates back to 1991, when the world’s first commercially available laser tracker was launched.

When Leica Geosystems laser trackers first hit the market nearly 20 years ago, they started quite a revolution in the way tooling was inspected and the way that jigs were built. Instead of relying on master gauges and references, and the eagle eye of a skilled operator sighting optics and theodolites, it was now possible to conduct simple, operator-independent measurement tasks by merely placing the reflector on the point being inspected. Because a laser tracker operates in 3D XYZ Coordinates – rather than in 1D and 2D space, as is the case with theodolites – there is fairly little room for operator error.

In the early 1990s, as the manufacturing techniques started calling for ever-closer tolerances with part-to-part assembly and the importance of interchangeability of spare parts in aircraft service, BAE Systems started looking for a way to instil greater repeatability and higher accuracy for its measurement tasks, possibly reducing the degree to which the quality of its metrological measurements depended on the skill of the operator.

The primary concern was to assure absolute constancy in tooling, keeping the measurement equipment up to date. BAE Systems was not so much interested in an off-the-shelf solution but in finding a business partner who was going to be there for them in the long run. With industrial metrology, equipment acquisition is merely the first step; BAE Systems needed a reliable partner for solving issues as they come up, and keeping an eye on future developments and trends in industrial metrology, thus making sure they are always one step ahead of the game.

And that’s how the partnership between BAE Systems and Leica Geosystems was born: a symbiotic relationship in which a brand-new technology was being put under test by an industry leader in aerospace manufacturing. The third-ever laser tracker produced, belonging to the now-legendary SMART series, was delivered to BAE Systems– and is still fully functional and in operation, which is a remarkable feat for a complex piece of electronic equipment, but is also a tribute both to Leica Geosystems’ quality of manufacturing and commitment to excellent service.

Another example of Leica Geosystems and BAE Systems working together is Axyz, the proprietary modular software for build and inspect applications. Used by thousands of customers today, it was initially developed specifically for BAE Systems based solely on their needs.
When laser tracking was first introduced at BAE Systems, it took some time to convince traditional craftsman of the benefits its use would bring – people are inherently reluctant to change, and traditional skills are slow to change. But it was the laser tracker’s ability to measure and inspect with repeatable, accurate measurements, and a user-friendly software interface, that yielded savings in both time and money. These concrete savings were pivotal in winning the metrology staff over. After all, they were dealing with brand-new technology with few precedents. However, over the years BAE Systems grew to be one of Leica Geosystems most valuable customers, using more than twenty laser trackers from all successive product generations within their Samlesbury Site assembly facilities.

It was only fitting that BAE Systems would be the first customer to take delivery of Leica Geosystems’ stunning new Absolute Tracker, officially launched in February 2008. Signifying both the value given to BAE Systems by Leica Geosystems but also manifesting the aerospace manufacturer’s enormous trust placed in the Swiss company, a zero-series Absolute Tracker was delivered to BAE Systems in December 2007 under a veil of secrecy.

BAE Systems was the ideal candidate for the flagship delivery: the company has enormous experience in using Leica Geosystems laser trackers dating back to 1991. Twelve systems are used in tooling applications, and several more for the assembly of very large components. As a result, the company’s staff has excellent product knowledge and can adapt the laser tracker to exactly what is needed, using different software for different applications. BAE Systems’ metrology specialists have over the years developed a great sense for what to measure, and, more importantly, how to measure it. The feature they have grown to appreciate most is the equipment’s predictable, unrelenting dependability of both accuracy and operation.

Philip Entwistle, a long-time user of Leica Geosystems laser trackers, explains: No two measurement jobs are the same: we are constantly dealing with different aircraft or different parts. And it’s amidst this mindboggling unpredictability that we need metrology equipment that is fail-safe and delivers predictably reliable results measurement after measurement, day after day, year after year. With the new Absolute Tracker, its much smaller size lets us bring it inside an aircraft cockpit, something that we were unable to do with the previous generation.

Our laser trackers are put to a lot of tough work; they are sometimes laid out flat on the floor to measure from underneath an aircraft or hung upside down, yet they work as specified without complaint. The most assuring characteristic of the Leica Geosystems equipment is its quality.
Not wanting to turn a deaf ear to new ideas, we performed some benchmark testing a couple of years ago, but these tests merely re-confirmed our initial healthy assumption that the laser trackers from Leica Geosystems are the best on the market. We know they work as specified and require virtually no tweaking on the part of the operator. Despite being moved around all the time, other than the yearly maintenance performed by Hexagon Manufacturing Intelligence, our laser trackers need no hourly or daily intermediate compensation routines. No other laser tracker manufacturer can make that claim.

Other benefits of using the new Absolute Tracker are its much smaller weight and size. Now it can be easily unloaded by only one person, yet despite a substantial weight reduction compared to the LTD series it replaces, the Absolute Tracker sports substantial gains in both mechanical and thermal stability.

Thanks to the systems’ portability, BAE Systems is able to offer metrology services to other companies as well. It has entered a long-term agreement with MAS (Military Air Solution), whereby BAE Systems provides various measurement services, from concept creation to end-of-lifecycle management for this project by the British Ministry of Defence.

Keeping abreast of the current development in the industrial metrology, BAE Systems decided to order an Absolute Tracker capable of being retrofitted for 6D measurements with the hand-held Leica T-Scan. The company is closely looking at the hand scanner for cycle checking of jigs in assembly. By being able to gather millions of data points within minutes, the Leica T-Scan could provide instant primary evaluation of the dimensional integrity of a project. Thanks to graphic representation of measurement data, which can be superimposed over CAD drawings, deviations are visible immediately, and corrections can be made if need be without having to first complete the entire jig. These intermediate checks have the potential of significantly reducing production times.

BAE Systems is also interested in other TProducts, such as the Leica T-Probe, which lets the operators inspect points to which no direct line of sight exists without having to reposition the laser tracker.
Nigel Gore, Business and Process Development Manager, has some final thoughts about the new Absolute Tracker: It sports a plethora of innovative features that help it rise above anything else available on the market. The Quick Release feature is great. The users know how easy it is to mount and dismount the laser tracker from the stand, and are therefore less likely to show reluctance in moving the equipment around, thus speeding up measurements. We also have great automated reporting tools. In addition, the Absolute Tracker takes a mere five minutes from the moment it is powered up to the time it can start measuring within spec. And it stays within spec throughout the day, which is the best indicator for the solid design both inside and out. All in all, our tooling department greatly benefits from these new features, doing its part to keep us ahead of the competition.